No. It’s not something dirty. Some call it a Batman angle, oblique angle or German angle. This filmmaking tactic uses the tilt of the camera to set a mood of tension or emotional turmoil in the world of the subject being filmed.
The reason it is called Dutch angle is rather funny. The Angle was a filmmaking technique heavily practiced in Germany in the 30’s and 40’s, earning the title “Deutch” (German) – but frequently confused with Dutch because of the English language. (We actually did not know the history of this – so I Googled.)
By leaning the camera to one side, so that the shot gets a diagonal axis, you achieve an unsettling mood. From there the camera can pan or track just like the DP or director desires – depending on what the vision for the scene is of course. While many who use this filmmaking technique do so keeping the angle static, there are some examples of moving Dutch angles out there.
The reason some Brits call it Batman angle is because, well duh, the series by the same name assigned each character with its own angle (!) hence creating a 1966 broadcast adventure that may have left some reaching for their nausea pills. Another example is also one of my personal favorites: The Third Man (1949) – this film used plenty of Dutch angles. Since the protagonist finds himself in unfamiliar territory, it suited the story perfectly. In iconic blockbuster Titanic, James Cameron also tilted his camera for the sinking of the ship – here we may care less about why, but can just simply say that it worked. At least for him. Whether TV creation of legendary filmmaking, the Dutch angel has made itself famous plenty of times.
Of course, as with all filmmaking tools and techniques – it only really works when it fills a purpose with your story!
Good luck!